1. Field of the Invention
The present invention relates to a check detector for glass bottle neck and finish portion.
2. Description of the Prior Art
In manufacturing glass bottles, there are cases in which so-called checks like cracks or seeds and blisters are generated in the wall thickness of the neck and finish portion.
For the seeds and bisters, no problem is caused in the viewpoint of products when they are small, but since the checks are critical defects that would result in breakage of glass bottles, the presence of checks is optically detected.
There are many types of checks that can be generated in a glass bottle neck and finish portion, such as those generated in simple threaded necks and necks for crown caps. For example, in the simple threaded neck and finish, several types of checks such as vertical, horizontal, and other checks may exist, but to optically detect the presence of these checks by types, the following method was conventionally used. That is, in the course of the handling route the, transfer of the glass bottles was intermittently stopped and with glass bottles rotated at the stopped position, a light emitter for emitting the neck and finish portion of the rotating glass bottle with light was located in the width direction on one side of the handling route, while a light receiver for detecting the reflected light totally reflected at the checks at the glass bottle neck and finish portion was located on the other side in the width direction of the handling route, and based on an output when the light receiver received the reflected light, the existence of, for example, vertical checks was detected.
Now, since the checks are generated without any directionality, checks must be detected with the following points taken into account. That is,
1 there is a boundary of reflection because checks shine due to total reflection, and PA1 2 there is a case in which reflected light due to checks may not exit to the outside. PA1 1 because there are extremely many combinations of emitters and receivers, the detector directly detects even the light transmitting through the neck and finish portion if detection is carried out at one place only, and PA1 2 total reflections other than vertical checks are also detected. For example, reflected light which is totally reflected at the mold seam formed at the glass bottle neck and finish portion is also detected, and there is a case in which non-defective glass bottles may be judged defective. PA1 3 when a plurality of emitters are simultaneously lighted, that is, when emitting beam is simultaneously emitted from multiple directions, the emitting beams interfere with one another, degrading the detection ratio, and at the same time, small seeds and bisters generated in the neck and finish portion excessively reflect, resulting in degraded detection accuracy. And for the corrective actions, turning off part of the emitters and receivers as required among a plurality of pairs of emitters and receivers, or degrading the detection sensitivity may eliminate the combination required for essential vertical check detection, resulting in degraded detection ratio. PA1 (A) the results obtained by arrangement of a plurality of pairs were to detect the presence of vertical checks. That is, for example, vertical checks at the top (upper vertical checks), vertical checks at the intermediate portion (middle vertical checks), vertical checks at the bottom (lower vertical checks), etc. generated in this order at the top, middle, and bottom positions of the neck and finish portion were unable to be identified and detected. PA1 (B) because, vertical checks were unable to be sorted unless influences of noises contained in detection signals taken into the receiver were reduced, the data corresponding to the detection signal must be differentiated at the signal processor mounted at the stage after the receiver. That is, because the detection signal has an inclination corresponding to the signal of vertical checks for each vertical check appearing in the above-mentioned data, it is necessary to perform processing to remove the noise by carrying out time differentiation and to leave vertical check signals only.
Consequently, hitherto, in order to improve the detection accuracy in detecting the presence of, for example, vertical checks, one each of light emitter and light receiver is paired, and a plurality of pairs of emitters and receivers are installed. And by varying the light emitting direction of the emitter and light receiving direction of the receiver for each pair and at the same time giving consideration to the arrangement of a plurality of pairs for easy detection of vertical checks, detection of vertical checks is able to be carried out under various optical conditions.
However, there are still the following problems:
By the way, the present applicant proposed a check detector of a glass bottle neck and finish portion with emitters and receivers arranged and suited for vertical checks detection (Publication of Unexamined Patent Application No. Hei 4-294262) but even if the above-mentioned problems may be able to be overcome,
In addition,